1. To observe mosquito larva density degression rate , both hydrophytes and fishes death rate.

2. Ornamental hydrophyte is an indispensable material for afforestation,(Sentencedict.com ) beautification and purification of waterscape and also a main element in making up gardening waterscape.

3. 14 Ornamental hydrophyte is an indispensable material for afforestation, beautification and purification of waterscape and also a main element in making up gardening waterscape.